Steam Turbine Seal Upgrades
As steam turbines age, components typically distort from original design specifications. Overhauls using standard seals made to the original design specifications can cause rubs, leaks and subsequent loss of efficiency and reliability.
EthosEnergy custom fits labyrinth seals to ensure a round bore and the right clearance regardless of the condition of the case. Detailed measurements, manufacturing, and final CNC machining on-site with our portable machining centers ensures the desired tight clearance. This process provides the performance recovery you expect when overhauling your steam turbine.
Labyrinth or conventional packing rings, that are installed in diaphragms or blade carriers, function is to minimize steam leakage. The packing rings incorporate fins which seal to the steam turbine rotor and create a torturous path which minimizes steam leakage. A tight effective seal allows steam to flow through the steam path as intended and maximizes the performance of the steam turbine. Tight efficient seals are damaged when the rotor travels through its critical speed and vibration results. Excess seal clearance results in a significant loss in performance, thus steam turbine owners should consider replacing labyrinth packing at each outage. EthosEnergy has the ability to replace these important components during a standard outage window so that the steam turbine can operate at its maximum efficiency
What can we do to help?
- Trained technicians take detailed measurements early in the overhaul to understand the magnitude of rotor and holder deviations so that new seals can be sized to achieve the desired clearance.
- EthosEnergy has developed a computerized distortion assessment program to evaluate the measurements and design new packing rings to the out-of-round or non-standard condition.
- EthosEnergy’s design engineers size the seals’ hook fit and teeth to achieve the desired clearance to the shaft. The final product may have a round or elliptical bore or hook to compensate for casing and holder deviations.
- During installation, EthosEnergy technicians use our portable machining centers and CNC lathes to fit the packing rings into their holders. Butt clearances are cut to ensure that the ring seals between the segments at operating temperature. Pin slots are machined to retain the packing in the holders. For more information, see our web page on
- After the ring is installed, the final clearance is verified by comparing tooth height with the shaft diameter.
Why choose EthosEnergy for your packing needs?
With EthosEnergy’s Custom Fit Labyrinth Seals, you will realize the following benefits:
- Correct seals made to order during the outage means no more obsolete inventory, no “last-ditch” parts orders.
- Custom-fit seals compensate for case distortion and return bore to proper round condition to ensure a tight clearance all-round.
- Tight clearances improve turbine performance.
- For units with “bottom humping” problems, customized elliptical bores can help prevent rubs and loss of efficiency
- Custom manufacturing during the overhaul eliminates inventory carrying costs.
- Steam turbine outages may be only every 5, 7 or 10 years. Take the opportunity to replace seals and run your unit efficiently through the next outage cycle
Get in touch today and learn more about our Custom Fit Labyrinth Seals